The movement of a piston is one of the best known forms of transferring linear motion into rotary motion, which is present in internal combustion engines.
As an example of a motor used for mixing drinks, U.S. Pat. No. 3,030,082 illustrates a motor coupled to a rotating device and a linkage member attached to the rotating device for a drink mixing device by a first ball mechanism that causes not only a pivoting motion, but also a rotation of a heavy rotating member (labeled 26 in FIG. 2 of the reference) about the axis of a rod (labeled 18 in FIG. 2 of the reference). However, a directing mechanism in the example is formed by the rod (labeled 18) fixed to the top of a lid closing a container and a second ball mechanism (labeled 21 in FIG. 3 of the reference) disposed above the cap and articulating engaged in a stationary frame (labeled 14 in FIGS. 2 and 3 of the reference), which is fixed in position relative to the drink mixing device.
However, the motion induced by rotation of the motor in U.S. Pat. No. 3,030,082 is not a natural shaking motion. Instead, the rotary motion of the motor and movement of the rod through the second ball mechanism provides for a limited, rotation about the axis of the rod (labeled 18), a limited orbital motion of the top of the container, and a slightly greater orbital motion of the bottom portion of the container. The reference teaches that this motion is preferred for mixing of drinks, because it overcomes all of the disadvantages of prior art devices, including poor agitation, inefficient mixing, a need for internal agitators or beaters, complicated structure, intricacy, bulkiness and impractical costs to manufacture, while thoroughly mixing drinks. However, the reference teaches that thorough mixing within the container is only achievable by a combination of the orbital motion of the container and the rotational motion of the container about the axis of the rod, which is brought about by the swinging from side to side of a C-shaped member (labeled 26 in FIG. 2 of the reference). See col. 2, lines 30-48. Thus, this reference teaches away from a cocktail shaker having a more natural motion that replicates that of a hand mixed cocktail. The throw (i.e. the length of movement from beginning of movement in one direction to return movement in the opposite direction) is very limited in this example of a drink mixer and in other prior art mixers. Indeed, it could be argued that the orbital motion presents no abrupt change in direction, as occurs in a hand shaken drink. The reference teaches that the only abrupt change of direction occurs due to rotation of the container about its longitudinal axis (i.e. the axis of the rod) from the weight of the C-shaped member.